Every photograph stops time. This is the most banal, technical fact about the medium and also the source of its uncanny and remarkably durable power. The relentless momentum of mundane existence is stilled by the shutter, and some of the mysteries implicit in everyday life open up. A moment — of high artifice or raw candor, of posed elegance or composed chaos — is captured and then, later, delivered to our contemplative gaze.

We, the beholders, are always late to the scene, which makes looking at a photograph a species of time travel. We look back, aware, at least unconsciously, that the world has moved on. After a while, so do we, turning the page and returning the image to its natural state as a permanent piece of ephemera. But sometimes we wonder: What happened next?

Thousands of photographs have appeared in the magazine. More than 250 of them — revealing portraits of the famous; documents of atrocity and heroism; sensitive studies of everyday life; unclassifiable works of art — have been collected into a book, “The New York Times Magazine Photographs,” edited by the magazine’s director of photography, Kathy Ryan, to be published in October by Aperture. The original images in this portfolio appear in that volume and make their second appearances in the magazine. Each is accompanied by a new picture of the same subject, in most cases taken by the original photographer.

The updates go some way toward answering the question that trails people who have endured a brief spell of media attention: Where are they now? We discovered them on the brink, in the midst or in the wake of important events. Here was a young model stepping out into a promising career. Here was a mother learning to care for her newborn daughter. Here was a firefighter struggling in the aftermath of a trauma both public and personal.

And now? People have aged, grown up, survived, changed. Nothing is the same. Everything the camera sees is as strange, as distressing and as beautiful as it ever was.

"Don't have a baby." That would be the sensible me now telling the 15-year-old me. That would be No. 1. "You're too young; go to college." And, "boys aren't everything." After my daughter Chastity was born, I stayed in Brooklyn wtih my mother. Victor, the baby's father, did what he could. ANd then seven years later I had Jennifer, and five years after that I had Jonathan. Right about when Chastity was a senior in high school, I moved to Troy, NY., after Jonathan's father and I broke up. It was April '95. I got an apartment in the projects with $300 in my hand and three kids. And I lived in that apartment for 10 years before I got a house from Habitat for Humanity. I got my G.E.D and made sure all my kids graduated from college. My chances of coming out the way I did were slim to none. I mean, I could have gone down a different path, but you know, God was always with me. I found a job at Rensselaer Polytechnic Institute, and I work there now. I've been here for 15 years. I'm engaged now, and Chastity's a mom. She is 33 years old and has a 7-year-old little boy, and she's doing great.